CassandraState.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
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package com.hmsonline.storm.cassandra.trident;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import storm.trident.operation.TridentCollector;
import storm.trident.state.State;
import storm.trident.tuple.TridentTuple;
import backtype.storm.topology.FailedException;

import com.hmsonline.storm.cassandra.bolt.mapper.Equality;
import com.hmsonline.storm.cassandra.bolt.mapper.TridentTupleMapper;
import com.hmsonline.storm.cassandra.client.AstyanaxClient;
import com.hmsonline.storm.cassandra.exceptions.ExceptionHandler;

public class CassandraState implements State {
    private static final Logger LOG = LoggerFactory.getLogger(CassandraState.class);
    public static final int DEFAULT_MAX_BATCH_SIZE = 3000;
    @SuppressWarnings("rawtypes")
    private AstyanaxClient client = null;
    private int maxBatchSize = 0;
    private ExceptionHandler exceptionHandler;

    public CassandraState(AstyanaxClient<?, ?, ?> client) {
        this(client, DEFAULT_MAX_BATCH_SIZE);
    }

    public CassandraState(AstyanaxClient<?, ?, ?> client, ExceptionHandler exceptionHandler) {
        this(client, DEFAULT_MAX_BATCH_SIZE, exceptionHandler);
    }

    public CassandraState(AstyanaxClient<?, ?, ?> client, int maxBatchSize) {
        this(client, maxBatchSize, null);
    }

    public CassandraState(AstyanaxClient<?, ?, ?> client, int maxBatchSize, ExceptionHandler exceptionHandler) {
        this.maxBatchSize = maxBatchSize;
        this.client = client;
        this.exceptionHandler = exceptionHandler;
    }

    @Override
    public void beginCommit(Long txid) {
        LOG.debug("Begin Commit: {}", txid);
    }

    @Override
    public void commit(Long txid) {
        LOG.debug("End Commit: {}", txid);
    }

    @SuppressWarnings({ "unchecked", "rawtypes" })
    public void update(List<TridentTuple> tuples, TridentCollector collector, TridentTupleMapper mapper) {
        LOG.debug("updating with {} tuples", tuples.size());

        try {
            if (this.maxBatchSize > 0) {
                int size = tuples.size();
                int batchCount = size / this.maxBatchSize;
                int count = 0;
                for (int i = 0; i < batchCount; i++) {
                    this.client.writeTuples(tuples.subList(i * this.maxBatchSize, (i + 1) * this.maxBatchSize), mapper);
                    count++;
                }
                this.client.writeTuples(tuples.subList(count * this.maxBatchSize, size), mapper);

                for (TridentTuple tuple : tuples) {
                    collector.emit(tuple.getValues());
                }
            } else {
                this.client.writeTuples(tuples, mapper);
            }

        } catch (Exception e) {
            if (this.exceptionHandler != null) {
                this.exceptionHandler.onException(e, collector);
            } else {
                LOG.warn("Batch write failed. Triggering replay.", e);
                throw new FailedException(e);
            }
        }
    }

    public List<Map<?, ?>> batchRetrieve(List<TridentTuple> tuples, TridentTupleMapper tupleMapper) {
        List<Map<?, ?>> retval = new ArrayList<Map<?, ?>>();
        for (TridentTuple input : tuples) {

            try {
                Object start = tupleMapper.mapToStartKey(input);
                Object end = tupleMapper.mapToEndKey(input);
                List list = tupleMapper.mapToColumnsForLookup(input);

                Map<?, ?> colMap = null;

                // TODO break out different interfaces for different types of
                // queries, then come back and fix this.
                if (list != null) {
                    // slice query
                    colMap = client.lookup(tupleMapper, input, list);
                } else if (start != null && end != null) {
                    // range query
                    colMap = client.lookup(tupleMapper, input, start, end, Equality.GREATER_THAN_EQUAL);
                } else {
                    // fetch by key
                    colMap = client.lookup(tupleMapper, input);
                }
                retval.add(colMap);
            } catch (Exception e) {
                if (this.exceptionHandler != null) {
                    this.exceptionHandler.onException(e, null);
                } else {
                    LOG.warn("Cassandra lookup failed. Triggering replay.", e);
                    throw new FailedException(e);
                }
            }

        }
        return retval;
    }

}